NFL roster construction is a zero-sum game. For every big free-agent addition, another guy is out of a job. While fans watch the free-agent frenzy hoping for big moves, players worry about how it could cost them playing time. Or wins.

Here's a look at 10 players that have suffered collateral damage during the free agency period. Their football lives got more difficult over the last week.

If Greg Schiano had kept his job, Glennon had a shot to become a franchise quarterback. Now he's a backup behind Lovie Smith-approved Josh McCown. Glennon being named a backup was one of the biggest surprises in all of free agency thus far. Perhaps new offensive coordinator Jeff Tedford could help Glennon's career, but it's more likely that Glennon is stuck with an organization that doesn't love his skill set.

NFC South quarterbacks: Glennon will also have a tougher time if he does wind up hitting the field in 2014. Jairus Byrd makes the New Orleans secondary versatile and scary. The Falcons added impressive beef to their defensive line; they will be tougher to push around. And while Glennon doesn't have to worry about it, Tampa's defense is loaded after adding Michael Johnson to an already talented Bucs defense. Lovie Smith has the talent in place at every level of the defense to coach up another top-five unit.

Christian Ponder, Minnesota Vikings quarterback: It's clear Ponder is no longer the quarterback of the future in Minnesota. But he had a chance to rehabilitate his value around the league in a new offensive system before Matt Cassel re-signed. The Vikings are essentially telling Ponder that he's not even good enough to compete for snaps with a rookie-to-be-named later. He went from a No. 12 pick to a No. 3 quarterback quickly.

Knowshon Moreno, Andre Brown and Jared Allen: These are three free agents that have seen their markets rapidly shrink over the last week. No running backs are getting big money, and Moreno might have priced himself out of any interest (if there was interest in the first place). Moreno might have to accept a low-cost, one-year deal somewhere despite gaining over 1,500 yards from scrimmage with 13 touchdowns. The Broncos have shown no interest in bringing him back. Brown is nearly in the same boat. The Giants replaced him with Rashad Jennings and Peyton Hillis.

Tony Romo, Dallas Cowboys quarterback: The Cowboys' defense continues to get worse, which Romo will somehow be blamed for eventually. Dallas is thin at wide receiver and running back, and they don't have the cap room to fill those holes.